Efficient gene delivery with osmotically active and hyperbranched poly(ester amine)s.

Area of Science:

• Biomaterials Science
• Gene Therapy
• Polymer Chemistry

Background:

• Nonviral gene vectors are crucial for gene therapy.
• Existing vectors like polyethylenimine (PEI) and lipofectamine have limitations.
• Developing safe and efficient gene delivery systems remains a challenge.

Purpose of the Study:

• To synthesize and evaluate novel degradable, hyperbranched poly(ester amine)s (PEAs) as nonviral gene carriers.
• To assess the DNA condensation, biodegradability, toxicity, and transfection efficiency of PEAs.
• To investigate the mechanism behind PEAs' gene delivery capabilities.

Main Methods:

• PEAs were synthesized via Michael addition of glycerol triacrylate (GTA) and low-molecular-weight polyethylenimine (LMW-PEI).
• DNA condensation, particle size, and surface charge were analyzed.
• Degradation rates, cytotoxicity in three cell lines, and transfection efficiency (luciferase assay) were evaluated.
• In vitro and in vivo gene expression studies, including aerosol administration, were performed.
• Endosomal buffering capacity was assessed using bafilomycin A1.

Main Results:

• Synthesized PEAs effectively condensed DNA into particles <200 nm with suitable surface charges (15-45 mV).
• PEAs exhibited controlled degradation with half-lives >12 days and were nontoxic.
• PEAs demonstrated superior transfection efficiency compared to PEI 25K and Lipofectamine.
• The GTA/PEI-1.2(1:4) ratio showed highest efficiency in HepG2 cells, with significant in vitro and in vivo gene expression.
• Results indicated a hyperosmotic effect and endosomal buffering capacity, contributing to high transfection rates.

Conclusions:

• Degradable, hyperbranched PEAs are effective and safe nonviral gene delivery vectors.
• The synergistic effects of the glycerol backbone and PEI's endosomal buffering capacity enhance gene delivery.
• PEAs show significant potential for both in vitro and in vivo gene therapy applications.